Solid-State Power Controller With Deterministic Hardware Protection
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Solution Overview
Problem
Conventional solid state power controllers for aircraft are complex, prone to failure, and require frequent maintenance due to mechanical and thermomechanical stress, which compromises safety and reliability in electric vehicles like eVTOLs.
Innovation Solution
A solid state power controller with a semiconductor switching unit and a non-programmable state machine that switches between conducting, non-conductive, and intermediate states, utilizing non-programmable electronic components for deterministic behavior and simplified testing and certification, incorporating current, temperature, and voltage sensors for overcurrent and temperature protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electromechanical switches and thermal fuses are used for power control, then basic power switching and protection functions are achieved, but mechanical complexity, mass, and maintenance requirements increase significantly
Solution Approach 1:
The patent replaces electromechanical switches with solid state power switches (semiconductor devices) and thermal fuses with electronic overcurrent protection circuits. This substitution eliminates moving parts, contact erosion, and arcing issues inherent in mechanical systems, thereby reducing mechanical complexity while maintaining or improving reliability and protection functions
Solution Approach 2:
The patent extracts and eliminates the mechanical components (contactors, thermal fuses) from the power control system, retaining only the essential protection functions through solid state implementations. This removal of mechanical elements directly reduces device complexity and maintenance requirements while preserving the core power control and protection capabilities
2Reliability
If complex electronics with redundancy are used in solid state power controllers, then safety critical functions are improved, but failure conditions and software bugs increase
Solution Approach 1:
The patent extracts and removes programmable microprocessors and complex control electronics from the safety critical power switching functions. By eliminating software and complex programmable logic from the power path control, the patent reduces potential failure modes related to software bugs and programming errors while maintaining safety through simpler, more reliable solid state circuitry
Solution Approach 2:
The patent replaces complex programmable electronics with dedicated solid state power switches and simple overcurrent protection circuits for safety critical functions. This substitution eliminates the complexity of programmable systems while maintaining the essential protection capabilities through hardware-based solid state implementations that are inherently more reliable
3Device complexity
If solid state power switches are used to reduce mechanical complexity, then device mass and maintenance are reduced, but inrush current and power dissipation increase
Solution Approach 1:
The patent implements a pre-charge circuit that activates before the main power switch closes. This pre-charge circuit gradually charges capacitive loads to the supply voltage level before full power connection, preventing inrush current spikes and reducing instantaneous power dissipation in the solid state switch
Solution Approach 2:
The patent introduces a pre-charge circuit as an intermediary between the power source and the main load. This intermediate circuit manages the power transfer by gradually charging capacitive elements before full power connection, thereby mediating the inrush current issue and reducing power dissipation in the main solid state switch
Data Source
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AI summary
Provided is a solid state power controller (SSPC). The SSPC comprises a power supply line configured to be connected between a power source and a load. Further, the solid state power controller comprises a semiconductor switching unit provided on the power supply line and configured to switch between at least two states according to a command signal. The at least two states include a conducting state and a non-conducting state. Further the solid state power controller comprises a state machine, which is configured to exhibit at least two states, including an ON state and an OFF state. The state machine is further configured to output the command signal according to a current state of the state machine.